This invention relates to form-work of the kind used for the construction of concrete decks, roadways, sidewalks, etc.
Poured concrete structures formed along the surface of the ground, such as concrete decks, roadways, sidewalks, etc. are typically constructed by preparing a firm bed upon which the deck is to rest. Border defining forms are provided for confining the uncured concrete mixture to a desired border contour, which may be straight or curved. A concrete mixture is poured over the prepared bed to fill the form and the surface of the poured concrete is trowled. After the concrete has cured, the forms are removed.
Two types of form-work are typically used for constructing concrete decks, namely structures of wood formed of boards and stakes fastened by nails and structures of specially formed metal form boards and stakes held together by rigid metal wedges. The wood form-work structures are typically constructed by driving stakes into the ground at intervals along a stake line that follows the desired edge contour of the deck. Then, boards are placed against the stakes and are nailed thereto. Usually, the stakes are displaced by the force of nailing, making it virtually impossible to locate the edge board at the precisely desired location. Moreover, the edge boards tend to break while being dismantled and they typically have a very low number of repeated uses.
The metal type form-work structures have been known for a number of years and typically include a metal formboard with connector means for connecting to stakes. One such device is described in Langford, U.S. Pat. No. 3,910,545, issued Oct. 7, 1975. In this design a steel wedge is driven through a projecting flange of an edge plate. The repeated wedging of the stake within the flange causes gauling of the stakes and/or the flanges. As a consequence, the accuracy of the system deteriorates with use.
Another type of metal form-work is described in Stegmeier, U.S. Pat. No. 4,340,200 issued July 20, 1982. In that design, a spring clip arrangement is utilized which hooks around the edges of the edge plate of the form-work. A stake passes through the clip member. However, this system does not provide a solid wedging system and relies on a spring clip for the accuracy of location. This spring clip assembly is both difficult to manufacture and difficult to use.